【作者】 高艳宏；

【导师】 李广田；

【作者基本信息】 东北大学 ， 钢铁冶金， 2005， 硕士

【摘要】 随着纯净钢冶炼技术的不断进步和对钢水纯净度要求的提高,采用优质精炼渣进行炉外脱硫处理己成为目前国内外许多研究的焦点问题。根据不同的钢种选择合适的精炼渣成为目前研究精炼渣的主要目的。 本课题从前人的工作基础上出发,依据冶金的热力学和动力学理论,寻求一种低熔点、高熔速、脱硫效果好的精炼渣。运用二次正交回归的实验方法,设计出以CaO-Al₂O₃为基体,MgO、BaO、CaF₂为辅料的精炼渣。按不同量的原料配比进行了精炼渣的熔点、熔速测试实验和脱硫实验,回归出了组分与熔化温度、熔化速度和脱硫率的数学模型,讨论了组分对精炼渣高温性能和脱硫率的影响;采用光学碱度理论计算了每组渣样的硫容量,可用于比较渣脱硫性能的优劣。研究中得出的精炼渣组分重量百分比和脱硫率、熔化温度、熔化速度之间的数学模型具有很高的置信度,实验数据与所采用的数学模型是比较符合的。综合考虑各种因素,得出本研究条件下各组分的最佳含量为:Al₂O₃/CaO=0.7,7%MgO,9%BaO,8%CaF₂,6%SiO₂。 本研究对优选出来的精炼渣样的粘度、表面张力和熔态密度进行了进一步的测定,测得的结果恰在前人认为具有良好性能的经验数值范围内,说明该渣性能优良。最后用优选出来的精炼渣在首钢第二炼钢厂进行了工业性试验,发现该精炼渣熔点低、熔速快,使用后缩短了精炼周期,节约了电耗,降低了成本;平均综合脱硫率达到了73.2%,最高达到了83.8%,较报道的58%有了很大的提高;成品中[%S]可降至0.005%～0.011%（平均0.007%）,基本可实现钢液的深脱硫。另外该渣还具有一定的脱氧、去夹杂效果,经对铸坯进行纵裂、中心裂纹、凹坑、夹杂等检查,未发现任何产品缺陷,铸坯合格率百分之百。由此可见,该渣具有较好的应用前景。更多还原

【Abstract】 With the progress of the clean steel smelting technique, desulphurization in the secondary refining process with fine refining slags has become a focal problem concerned all over the world. The main purpose is how to choose proper refining slag in accordance to different steel grade.Based on predecessor’ work, the author seeks the refining slag with the low melting point, high melting velocity according to the melt thermodynamics and kinetics theory. The CaO-Al₂O₃ base slags containing MgO, BaO, CaF₂ as auxiliary components are designed by quadratic orthogonal regression method. The author conducts melting point, melting velocity experiments and desulphurization test in the condition of charging different quantities of raw materals. Base on experimental results, mathematical models between composition and properties were established. And the effects of composition on molten properties and desulphurization rate were discussed. Optimized composition was obtained by orthogonal direct-visual method. Optical basicity was used to calculate sulfur capacity. The confirming test shown that the mathematical models were highly reliable. By comprehensive consideration of physicochemical properties of slag in the study, the optimized composition of refining slag ought to be 7%MgO, 9%BaO, 8%CaF₂, 6%SiO₂ and Al₂O₃/CaO=0.7.The physical properties such as viscosity, surface tension and melting density at high temperature have been measured and the properties are excellent compared with empirical value. The optimal refining slag is examined at the second steel mill of ShouGang. It can shorten refining period and save energy consumption, so decrease cost. Its average comprehensive desulphurization rate reaches 73.2%, and maximum value is 83.8%. The value is higher by contrast with 58% reported. [%S] in steel can be reduced to 0.005%⁰.011%（average 0.007%）, which can satisfy the requirement of deep desulfurization. In addition, the slag possesses certain abilities of deoxidation and removing inclusions. Any product defects have not been found by inspecting slab about longitudinal, central split, piezoglypte, inslusion etc, and qualification rate of更多还原